Well, I'm almost at the 20,000km mark and I can still hear some humming noise, although it is a lot quieter than before. (I had a long spell when I thought that the sound was gone, but alas.) Not sure if other members have this prb. For me, the occurrence is 50% of the time I drive. I dunno if anything can be done about it since some members have replaced their entire fuel tank but the noise still persists.

BMW replaced my LPFP in October 2009 (~5800km). But the humming noise can back within a half year, but not as loud as the previous LPFP. It seems the noise level has stabilized in the last 15 months, ~30000kms. I can only hear it when the fuel tank level is lower than 50%.